Php-nuke and MySQL trouble

I have recently installed php nuke into my web host by extracting all contents of "html" folder into my main directory. I went to "http://www.myhost.com/admin.php" to find this error message:

Warning: main(language/lang-.php): failed to open stream: No such file or directory in /home/killtpfn/public_html/mainfile.php on line 183
Warning: main(): Failed opening 'language/lang-.php' for inclusion (include_path='.:/usr/lib/php:/usr/local/lib/php') in /home/killtpfn/public_html/mainfile.php on line 183
Warning: get_lang(admin/language/lang-.php): failed to open stream: No such file or directory in /home/killtpfn/public_html/mainfile.php on line 198
Warning: get_lang(): Failed opening 'admin/language/lang-.php' for inclusion (include_path='.:/usr/lib/php:/usr/local/lib/php') in /home/killtpfn/public_html/mainfile.php on line 198
Warning: head(themes//theme.php): failed to open stream: No such file or directory in /home/killtpfn/public_html/header.php on line 31
Warning: head(): Failed opening 'themes//theme.php' for inclusion (include_path='.:/usr/lib/php:/usr/local/lib/php') in /home/killtpfn/public_html/header.php on line 31
Fatal error: Call to undefined function: themeheader() in /home/killtpfn/public_html/header.php on line 47

It seems like I have to move all the php files to "maindir/home/killtpfn/public_html/"?